
#1
Dec2811, 12:15 PM

P: 33

1. The problem statement, all variables and given/known data
1.a block of mass 5kg moves on a rough horizontal plane with coefficient of friction (Dynamic) 0.2 under the action of a horizontal force of 30N. If the block starts from rest , find the distance it travels in the first 3 second. 2.a particle of mass 6kg,moving at 8m/s on a smooth horizontal surface, goes onto a rough horizontal surface with a coefficient of friction 0.25> Find the distance it moves across the rough surface before coming to rest. 3.This is my own question.Because I might get the concept of friction force wrongly It's been in my mind for about 3 days thinking of it A particle moving up a slope with a maintained speed of 1m/s In another situation a same particle moving up the same slope with a maintained speed of 5m/s Do the two particle use the same force? As the Coefficient,mass,gravity,angle of slope are the same 2. Relevant equations F/N =u(Mew) F=ma s=ut+1/2 at^2 Anyhow Regarding the equation, Relating The Momentum and Force F=ma F=m x v/t Ft=mv So If The Force is 15N and the object moving at a constant velocity last for 3 seconds Ft=mv 15(3) = MV It will be 45 kg m/s ?? 3. The attempt at a solution 1. M=5kg Force=30N μDynamic = 0.2 μStatic = F/N (Force Used To Overcome the Static Friction)/(Normal Force) = 30/(30x9.8) = 0.1020 Initial Velocity=0 Final Velocity = 0 Time=3 seconds Distance = Unknown Untill This Step What Should I Do With the two different coefficient of friction?? 2. Upon This Stage I Do Realize that I'm Getting Stupiddd 



#2
Dec2811, 12:38 PM

P: 1,195

Static friction is not an issue in this problem. Sum the forces and proceed either by impulse momentum or by Newton's Second Law and velocityacceleration equation.




#3
Dec2811, 12:41 PM

P: 1,195

"A particle moving up a slope with a maintained speed of 1m/s
In another situation a same particle moving up the same slope with a maintained speed of 5m/s Do the two particle use the same force?" Yes. 


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